The Reforms That Built an Empire Before Gaius Marius, Rome’s armies were made of citizen-soldiers—farmers, laborers, and craftsmen who served part-time and returned to their fields when the campaign ended. It was a system built for a small republic, not a rising superpower. But by the late 2nd century BC, Rome was collapsing under pressure. Foreign threats grew, political chaos spread, and the old system could no longer supply enough troops. Marius changed everything. In 107 BC, he opened enlist